DETERMINATION OF TEMPOROMANDIBULAR-JOINT FLUID CONCENTRATIONS USING VITAMIN-B-12 AS AN INTERNAL STANDARD

The aim of the investigation was to test the reproducibility and accur acy of a new method to measure temporomandibular joint (TMJ) fluid con centrations of various substances by saline washing, using exogenous B -12 as a marker. An in vitro test was first performed with glucose as a test substance. The difference between a B-12-calculated and known s tandard concentration of glucose was very small, Saline washing of the TMJ was performed on 13 patients having signs of TMJ arthritis, and t he aspirates obtained were analyzed for neuropeptide Y-like immunoreac tivity (NPY-LI) and interleukin-1 beta (IL-1 beta). Vitamin B-12 was m ixed with the saline immediately before injection, and a sample of the aspirate was later compared photometrically with the injection soluti on. There were positive correlations between saline aspirate and joint fluid concentrations for NPY-LI and IL-1 beta, and the correlations w ere stronger for saline aspirates with high joint fluid content. This study shows that the method is reliable for measurement of joint fluid concentrations of various substances, such as NPY-LI and IL-1 beta.